Mix cucumber, tomatoes, parsley, olives, onion, and feta in a large bowl.
Use a spoon or spatula to spread a dollop of hummus along the inside of each pita pocket. Stuff with vegetable mixture.
I used regular pita for this recipe, but found that the pita has a tendency to rip when stuffed. Pita pockets are a bit sturdier and will be less messy! Alternatively you can slice your pita into rectangles and use the hummus and vegetable mixture as a dip.